I can confirm this bug. It's unclear to me why this is necessary, but changing the line
ExecStart=/usr/bin/stubby to ExecStart=/usr/bin/stubby -C /etc/stubby/stubby.yml in /lib/systemd/system/stubby.service fixes the problem.
I can confirm this bug. It's unclear to me why this is necessary, but changing the line
ExecStart=/usr/bin/stubby to ExecStart=/usr/bin/stubby -C /etc/stubby/stubby.yml in /lib/systemd/system/stubby.service fixes the problem.